Author George RR Martin says the next "Song of Ice and Fire" book has a real chance of coming out in 2018.

But don't count on it yet.

In a weekend posting on his website, Martin wrote that he's working hard on "The Winds of Winter," the long-awaited sixth volume in the series adapted into the HBO hit "Game of Thrones." He added that he has "good days and bad days" and is still months away from finishing. Meanwhile, he thinks it's "likely" that he'll have his first "Fire and Blood" book out by late 2018 or early 2019. The new book is a history of House Targaryen, which has the motto "Fire and Blood."